1. Field of the Invention
The invention relates to an apparatus for dissolving gas in liquid, and more particularly to an apparatus for venting a bubble contactor employed to dissolve gas in liquid.
2. Reference to Prior Art
In many processes it is desirable to dissolve gasses in liquids. In one such process an apparatus for dissolving oxygen in water is employed in a water treatment system for removing fuel constituents from water contaminated thereby. The apparatus for dissolving oxygen in water, or "oxygenator", includes a bubble contactor having a somewhat complex design for routing water and gas bubbles. The bubble contactor includes a degas vessel and a downwardly diverging funnel-shaped member extending into the degas vessel for conducting a downflow of water into the degas vessel. The funnel-shaped member defines a bubble contact zone in which oxygen containing bubbles tend to suspend. Excess gas bubbles crowded out of the bubble contact zone escape from the bottom of the funnel-shaped member and ascend to a gas trap at the top of the degas vessel. The oxygenator also includes gas recirculation equipment and a gas vent system communicating with the gas trap for purging from the gas trap accumulations of gas in excess of that which the recirculation equipment can handle. The gas vent is manually operated and, when opened, results in a continuous gas loss which can be costly since oxygen enriched gases are expensive to produce. If the venting arrangement is left closed there is no protection against the build-up of a potentially combustible mixture of oxygen and fuel constituents.
Additional examples of oxygenators are illustrated in U.S. Pat. Nos. 4,477,393 issued Oct. 16, 1984 to Kos and 3,926,588 issued Dec. 16, 1975 to Speece. The venting arrangements employed in these constructions also continually vent gas from the system.